This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A373025 #4 Jul 22 2024 15:28:11
%S A373025 1,3,5,0,3,7,2,9,0,6,0,2,2,6,9,8,5,9,4,9,6,4,8,8,7,3,1,8,4,6,3,3,5,5,
%T A373025 8,5,0,2,8,7,3,5,7,0,4,9,0,3,7,9,3,5,3,2,6,0,3,6,9,4,0,5,3,3,4,6,5,0,
%U A373025 7,1,0,3,5,3,1,4,2,4,6,1,2,2,6,4,7,4
%N A373025 Decimal expansion of Sum_{k>=0} cos(k*Pi/5)/2^k.
%F A373025 Equals (23 + 3*sqrt(5))/22.
%F A373025 Equals Sum_{k>=0} cos(9 k*Pi/5)/2^k.
%F A373025 Minimal polynomial: 11 - 23 x + 11 x^2.
%e A373025 1.3503729060226985949648873184633558...
%t A373025 {b, m, h} = {2, 5, 1}; s = Sum[Cos[ h k Pi/m]/b^k, {k, 0, Infinity}]
%t A373025 d = N[s, 100]
%t A373025 First[RealDigits[d], 100]
%Y A373025 Cf. A373021 (includes guide to related sequences).
%K A373025 nonn,cons
%O A373025 1,2
%A A373025 _Clark Kimberling_, Jul 20 2024